Revert of [build] Fix default for target_arch

Revert of [build] Fix default for target_arch (patchset #1 id:1 of https://codereview.chromium.org/2040803005/ )

Reason for revert:
sysroot logic breaks "make arm"

Original issue's description:
> [build] Fix default for target_arch
>
> Fix after https://codereview.chromium.org/2028623002/
>
> BUG=chromium:474921, chromium:616032
> TBR=vogelheim@chromium.org, jochen@chromium.org
> NOTRY=true
>
> Committed: https://crrev.com/9dcb67dd174fefc98f9c964ef54fed8fe6feb224
> Cr-Commit-Position: refs/heads/master@{#36733}

TBR=vogelheim@chromium.org,jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:474921, chromium:616032
Committed: https://crrev.com/46d8293f50478be702ce00b6ae51f6491a552173
Cr-Commit-Position: refs/heads/master@{#36740}

[Michael Achenbach, 2016-06-06 11:00:13]

The CQ bit was checked by machenbach@chromium.org

[Michael Achenbach, 2016-06-06 11:00:14]

Created Revert of [build] Fix default for target_arch

[commit-bot: I haz the power, 2016-06-06 11:00:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2039853002/1

[commit-bot: I haz the power, 2016-06-06 11:00:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-06 11:01:49]

Description was changed from

==========
Revert of [build] Fix default for target_arch (patchset #1 id:1 of
https://codereview.chromium.org/2040803005/ )

Reason for revert:
sysroot logic breaks "make arm"

Original issue's description:
> [build] Fix default for target_arch
> 
> Fix after https://codereview.chromium.org/2028623002/
> 
> BUG=chromium:474921, chromium:616032
> TBR=vogelheim@chromium.org, jochen@chromium.org
> NOTRY=true
> 
> Committed: https://crrev.com/9dcb67dd174fefc98f9c964ef54fed8fe6feb224
> Cr-Commit-Position: refs/heads/master@{#36733}

TBR=vogelheim@chromium.org,jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:474921, chromium:616032
==========

to

==========
Revert of [build] Fix default for target_arch (patchset #1 id:1 of
https://codereview.chromium.org/2040803005/ )

Reason for revert:
sysroot logic breaks "make arm"

Original issue's description:
> [build] Fix default for target_arch
>
> Fix after https://codereview.chromium.org/2028623002/
>
> BUG=chromium:474921, chromium:616032
> TBR=vogelheim@chromium.org, jochen@chromium.org
> NOTRY=true
>
> Committed: https://crrev.com/9dcb67dd174fefc98f9c964ef54fed8fe6feb224
> Cr-Commit-Position: refs/heads/master@{#36733}

TBR=vogelheim@chromium.org,jochen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:474921, chromium:616032

Committed: https://crrev.com/46d8293f50478be702ce00b6ae51f6491a552173
Cr-Commit-Position: refs/heads/master@{#36740}
==========

[commit-bot: I haz the power, 2016-06-06 11:01:50]

Patchset 1 (id:??) landed as
https://crrev.com/46d8293f50478be702ce00b6ae51f6491a552173
Cr-Commit-Position: refs/heads/master@{#36740}